Looking down at their beautiful twin boys, Richard Woolven and his wife Sandra, realise how lucky they are to have a family of their own.

The 32-year-old computer programmer, who lives in Worcester, had suffered a testicular torsion in 1997 which occurs when the spermatic cord twists around the testes, cutting off blood supply.

However, the swelling was rectified by using drugs and at the time Mr Woolven’s GP told him his fertility would remain unaffected.

He met his wife Sandra three months’ later and the couple were married near Dijon, in France, in August 2004.

After trying to start a family for 18 months, Mr Woolven returned to his GP who only agreed to carry out a fertility test “to make me feel better”, but it revealed his level of follicle stimulating hormone (FSH) were the same as a post-menopausal woman and he had a sperm count of zero.

“It’s a difficult thing to come to terms with. You suffer a loss of something you never had, something you maybe had taken for granted, that you always felt would happen at some point in the future,” he said.

“I’d always thought I’d get married and have children – so for someone who’s wanted that for so long, being told you can’t is a very distressing experience.”

After much discussion the couple decided to undergo fertility treatment, using donor sperm, at St Jude’s Hospital in Wolverhampton.

Mr Woolven added: “Trying to make a decision over the characteristics you want the man who will ultimately get your wife pregnant, and be the father of your children, was not something I had ever contemplated before.

“We filled in the form and received details of the guy – we know what his occupation is, build, eye colour and personal interests – who was the best possible match for us.

“But it was a “take it or leave it” situation because there was such a shortage. If his samples didn’t work we didn’t know when or if we could try again because there weren’t enough donors to repeat the treatment.”

Sandra gave birth to twin boys – Alec at 4lb 14oz and Luka 6lb 2oz – at Worcester Royal Hospital on April 20, 2007.

Mr Woolven, who is also a trustee of the National Gamete Donation Trust, added: “It was an amazing moment. It’s impossible to describe because it’s a very long road and it wasn’t easy by any means, but I realise how lucky we’ve been to have our two healthy boys.

“If I knew then what I know now and I had the choice of using my own sperm or a donor’s, I would still want the kids I’ve got now, and if I met the guy responsible, all I could do would be to thank him and shake his hand.

“This man, whoever he is, has changed my life, our lives, for the better – I will never be able to repay him.”

But since donor anonymity was lifted in April 2005, by the Human Fertilisation and Embryology Authority, children conceived using donor sperm are allowed to trace their genetic parent through their donor register once they are 18.

However, dwindling numbers of donors means more couples are facing waiting lists of a year or more.

In 1996, 403 men newly registered with the HFEA as sperm donors, falling steadily over the following years to 247 in 2004.

Figures for 2006 showed a rise to 307 but fewer women overall were treated with donor sperm.

In 2005, 2,727 women were treated with donor sperm but this fell to 2,107 in 2006.

Dr Jackson Kirkman-Brown, Birmingham Women’s Hospital’s lead on gamete donation, explained that while there is an overall shortage of donors, Asian patients are facing a disproportionately long odds of being matched to a suitable donor.

Between 600 and 800 cycles of IVF/ICSI are performed at the hospital’s Assisted Conception Unit, of which about 100 use donor sperm.

Around 50 per cent of the unit’s patients are Asian, but only 10 per cent of donors on their books are Asian.

Dr Kirkman-Brown said: “Since donor anonymity was lifted in 2005 we have seen a change in our donors’ demographic, so where we were getting lots of students in their teens and 20s, we’re now seeing more mature men who have either opted not to have children or already have families and want to help someone else.

“Donors can only be used to help create up to ten families, including siblings, after which they are effectively ‘retired’.

“A large number of our patients are Asian, so the right match isn’t just about ethnicity but also religion.

“This is a Birmingham specific problem, it’s not really reflective of the national trend but only two of our 20 new donors are Asian, so we do need more ethnic donors.”

Mr Woolven urged all men, whether they consider themselves to be suitable sperm donors or not, to consider the plight of those desperate but unable to have children of their own.